Process for the manufacture of a welding wire, and welding wire

ABSTRACT

A process for the manufacture of a welding wire having a core of base welding steel provided with a covering of an additional element, which comprises depositing a coating of said additional element directly onto the core of base welding steel. Preferably the additional element is deposited by the method of evaporation under vacuum.

United States Patent 1191 Streel 1 Dec. 18, 1973 [54] PROCESS FOR THEMANUFACTURE OF A 3,637,421 1/1972 Gimigliaro 117 107 WELDING WIRE ANDWELDING WIRE 3,029,506 4/1962 Griffiths 117/207 3,102,827 9/1963Kriewall 117/207 Inventor: o nique homas ranco s Stree 3,421,952 l/1969Conrad et a1. 117/106 A Ougree, Belgium 3,438,802 4/1969 Kanter 117/106A 3,502,450 3 1970 M C 117/207 [73] Asslgnee: Cockenll-Ougree-Provldenceet 3,574,678 4197] l I 1 17/207 Esperance-Longdol en abrege 2,067,6301/1937 Franks 117/207 CockerilF, Seraing-lez-Liege, Belgium PrimaryExaminerA1fred L. Leavitt [22] Filed June 1971 Assistant Examiner-M. F.Esposito [21] App]. No.: 153,952 Attorney-Young and Thompson [30]Foreign Application Priority Data June 24, 1970 Belgium 42,869 [57]ABSTRACT 1 Cl 117/107 1l7/107-1, A process for the manufacture of awelding wire hav- 1 ing a core of base welding steel provided with acover- [51] Int. Cl B23k 35/00, C23g 1/00 ing of an additional element,which comprises depositl 1 Field of Search 106 A, ing a coating of saidadditional element directly onto 107-2 the core of base welding steel.Preferably the additional element is deposited by the method of evapora-[56] References Cited tio u der vacuum.

UNITED STATES PATENTS 4/1930 Miller 117/207 4 Claims, N0 DrawingsPROCESS FOR THE MANUFACTURE OF A WELDING WIRE, AND WELDING WIREBACKGROUND OF THE INVENTION This invention relates to a process for themanufacture of a welding wire in which a core of welding steel isprovided with a covering of an additional element.

It is known that for effecting electric arc welding with gas or flux,steel rods or wires of variable chemical composition are used dependingon the nature of the work to be done and the welding conditions.

While for the purpose of welding ordinary steels, one may use weldingrods having a composition close to that of these steels, having howevera low manganese content variable from 0.3 percent to 0.9 percent,welding of special steel and, more particularly, stainless steels,necessitates welding rods with a much greater manganese content. In thisinstance, the necessary manganese content may vary from 2 to 3 percent.

Moreover, when wearing members are to be strengthened, one uses weldingrods with a high content of manganese.

It is also known that the welding rods used at present sometimes have ontheir steel core a chemical coating or covering maintained by means of acement. In addition, it is also known to constitute the covering by anadditional metal cemented on the core of base welding steel and whosefunction is to increase the concentration of one of the components ofsaid base welding steel.

On the other hand, for welding with gas or flux, one uses bare oruncovered wires which generally are relatively thin with a highmanganese content and which sometimes are cut into rods.

Base welding steels-with high manganese content, as used for making rodsand wires for welding purposes are comparatively difficult tomanufacture. In addition, these steels have special mechanicalproperties such as a high hardness so that milling and extruding ofthese steels are difficult to effect.

For the above reasons, welding rods and wires with high contents ofmanganese are costly which is a disadvantage. The latter is furtherincreased by the fact that an increasing number of kinds of rods andwires are to be manufactured so as to correspond with different contentsof manganese for the purpose of meeting the needs resulting from moreand more diversified conditions of welding. The result thereof is thatthe number of rods or wires to be made of a given composition is neververy high, which causes difficulties of supply of base welding steel.

SUMMARY OF THE INVENTION The problem to be'solved by the presentinvention is to obtain a welding wire whose content of one of thecomponents of the base welding steel maysystematically be increased witha very high precision and according to varying degrees depending on theintended use. i I

A solution of said problem is provided according to the invention by amanufacturing process of a welding wire which comprises depositingdirectly onto the base welding steel wiretaken as a support, a coatingof an additional element whose proportion is to be increased withrespect to that of the base welding steel wire,

ing core of base welding steel covered or coated with an additionalelement.

DETAILED DESCRIPTION OF THE INVENTION According to a particular feature,the additional element is deposited onto the base welding steelsupporting core by the method'of evaporation under vacuum. The use ofsaid method is particularly advantageous due to the great variety ofcomposition which it permits one to obtain easily and systematicallywith an extreme precision.

According to another feature, the additional element composing thecoating deposited on the base welding steel supporting wire by themethod of evaporation under vacuum may be a pure metal such asmanganese, an alloy or silicon.

The present invention is simple to apply the process essentiallyconsists in coating a welding steel supporting wire with a layer ofadditional element on its entire lateral surface and with a thicknesssuch that after melting of the base welding steel supporting wire andsaid coating, there is formed a welding steel having the desired highcontent of said additional or filler element in the weld.

Thus, if it is desired to obtain a welding wire with a high content ofmanganese, one deposits by evaporation under vacuum, onto a commonwelding wire, man- 'ganese so as to form such a layer that, uponmelting,

there is formed a steel with the desired high content of manganese.

Because an apparatus for depositing a metal coating onto metal wire byevaporation under vacuum is already known, such apparatus will not bedescribed in detail in this specification.

Let it only be recalled that said advantageous apparatus comprises anenclosure in which there is a vacuum of about 10 Torr, said enclosurebeing traversed by the wire to be coated which passes along the axis ofa ring-shaped melting-pot surmounted with a cone of tantalum whose innersurface heated to a temperature of about l,00OC reflects the atoms ofmetal emitted from the melting-pot, the surface of which is bombarded byan electronic gun. When the melting-pot contains manganese which is ametal with high vapour pressure, it is impossible to cause the manganeseto melt because it sublimates as soon as its temperature reaches 1,500Cand its vapour pressure is 10 Torr.

which results in a welding wire composed of a support- This is perfectlysuitable for the deposition operation.

The weight of deposited manganese, which is of course variable dependingon the average content of manganese to be obtained in the weld, isdistributed as a layer whose thickness can be calculated from thefollowing simplified formula:

in which I PMn is the weight of manganese Pa is the weight of steel v eis the thickness of the layer, in mm I R is the radius of the wire, inmm dMn is the specific gravity of manganese da is the specific gravityof steel.

By applying the above formula, it is found that deposition of 1.5 grmanganese onto ordinary steel welding wire of 3 mm diameter and l mlength and containing about 0.4 percent of Mn, gives a coating formed bya layer of manganese with a thickness of 22 microns,-

which gives then by melting a steel having an average content ofmanganese of about 3 percent.

The present process makes it possible even to deposit elements otherthan manganese, e.g., silicon, vanadium, copper and alloys.

It is possible to obtain welding wires having as various contents asdesired for a given metal, starting from a supporting wire having asingle given composition, which is most inexpensive. In addition, thevarious contents may be obtained very precisely. One obtains thusentirely new welding alloys by applying a simple and easy method.

The welding wire may be subjected to subsequent operations such ascoating, winding or cutting according to its intended uses.

What I claim is 1. A process for the manufacture of a welding wire of arequired high composition in manganese, comprising forming a steel wirecore having a low content in manganese not more than about 0.9 percentby weight so as to enable the fabrication of the wire without breaking,and depositing on said wire core a coating consisting essentially ofmanganese by evaporation under vacuum to obtain a steel cored weldingwire, the thickness of said coating being such as to raise said lowcontent in manganese to a manganese content of about 2 to 3 percent byweight.

2. A process according to claim 1, in which said manganese has athickness of about 22 microns.

3. A welding wire consisting essentially of a core of base welding steelhaving a low content in manganese not more than about 0.9 percent byweight so as to enable the fabrication of the wire without breaking, anda coating deposited on said wire core by evaporation under vacuum andconsisting essentially of manganese, the thickness of said coating beingsuch as to raise said low content in manganese to a manganese content ofabout 2 to 3 percent by weight.

4. A welding wire according to claim 3, in which said manganese has athickness of about 22 microns.

2. A process according to claim 1, in which said manganese has athickness of about 22 microns.
 3. A welding wire consisting essentiallyof a core of base welding steel having a low content in manganese notmore than about 0.9 percent by weight so as to enable the fabrication ofthe wire without breaking, and a coating deposited on said wire core byevaporation under vacuum and consisting essentially of manganese, thethickness of said coating being such as to raise said low content inmanganese to a manganese content of about 2 to 3 percent by weight.
 4. Awelding wire according to claim 3, in which said manganese has athickness of about 22 microns.